1. Field of the Invention
This invention relates to hot beverage serving urns and methods of keeping the hot beverage hot while within the urn.
2. Discussion of the Prior Art
Coffee urns of the type into which coffee is directly brewed at a brewing location and then moved to a serving location where the coffee, tea or other brewed beverage is served from a serving faucet, or spigot, are well known in the art of brewing and serving of hot coffee and tea. In order to keep the brewed beverage at the desired temperature at which it was freshly brewed, it is generally preferable to fill the urn with the hot beverage. Such urns come in different sizes such as one, one and one half, two and three gallons.
A problem with such serving urns is that often the coffee becomes too cool for good quality before the urn is depleted. In order to overcome this problem, it is known to an internal or external electrically powered heating element. It is also known to insulate the urn to reduce heat loss after the urn is filled with beverage. Heat loss occurs by way of radiation. Heat loss also occurs by direct loss when hot beverage is served from the dispensing urn, and the heat of the beverage is physically removed from the beverage. As a consequence of such heat loss, the serving time during which the beverage is still above the minimum serving temperature, for best flavor and desirability, is only approximately one to one and one half hours if the dispensing urn is initially filled to capacity. If the urn is not filled to capacity but is only half filled, for instance, then the serving time may be reduced proportionately with the reduction in percentage of full capacity. Part of the problem is that the NSF and brewer industry standards require the use of stainless steel that has a relatively high rate of heat transfer.
The known ways of overcoming this serving time limitation include not moving the serving urn from the location at which it is brewed and keeping it on an external hot plate or other external heating element at the brewing location. This approach disadvantageously ties up the brewing location such that other urns cannot be filled, and, of course, demands that servers return to the original brewing location to serve the beverage into a smaller serving container such as a carafe or into a cup for direct service.
Alternatively, it is know to move the urn closer to the serving location and then place it on an electrical hot plate at another location or, to provide the urn with an internal heating element that is plugged into an AC power outlet for receipt of electrical power at a remote location in order to maintain the temperature of the beverage at the desired temperature. The need for a source of electrical power, at hand, to power the hot plate or internal heating element, and is not convenient when it is desired to locate the urn in a central location away from an AC power wall outlet. Even if there are floor outlets, if the urn is placed on a table, then a power cord must come up from the floor and rest upon table to reach the hot plate or the connection to the urn, itself, in the case of an internal, electrically powered heating element.
Another problem with electrical heaters is that controlling the heating element requires a thermo-mechanical or electronic thermostat to insure that not to much heat is added to the urn. Too much heat due to power surges or improper calibration can result in reduction of the beverage due to evaporation and overheating of the flavor elements of the brew. Both of these conditions may undesirably alter the flavor and aroma of the beverage being served. Coffee that is served too hot can also create risk of scalding and potential civil liability to the server. Likewise, there may be an increased risk of liability associated with electrical power cords lying on a service floor and hot plates and continuously electrically powered or thermostatically controlled electrically powered heating elements.
As a consequence of the problems associated with electrically powered heating elements and hot plates, noted above, and also with the non-heated, insulated urn which does not keep the beverage above a minimum desired temperature for longer than 1-2 hours, particularly in the case of less than a full brew capacity filling the urn, there is an unfulfilled need in the market of commercial coffee brewers and serving systems and the like for a serving urn that overcomes these limitations and disadvantages.
In accordance with the present invention, the problems noted above that are associated with the failure of non-heated urns to maintain heated beverages above a minimum time period desired by the commercial brewer user industry and the disadvantages associated with electrically powered hot plates or internal electrical heating elements, are overcome.
This objective is achieved by providing the urn with an associated heat generating pack, or warmer pack, that is neither powered by electricity nor flame but which, but after being heated itself, slowly generates sufficient heat to help maintain the temperature of the beverage above the minimum desired temperature. Preferably, in the case of a coffee brewer used to fill the urn, the heat pack is preferably rapidly heated during the brewing cycle duration of 2xc2xd minutes to four minutes when the serving urn is located at the same location as the brewer.
Alternatively, the heating packs are heated independently from the brewing process and maintained in a heated condition until needed. The heating pack is then later removably conjoined with the serving urn in a special compartment to help maintain the initial temperature of the brewed beverage in the serving urn. These packs, whether internal and fixedly attached to the urn, or detachable but adapted for mating connection with the urn, help maintain the temperature within the urn by giving off heat to the urn after the packs are no longer being heated, themselves.
Thus, the objective is achieved in part by provision of a self-heating beverage urn, having an urn body with an outer housing protectively containing a liner for storage of hot beverage, and a compartment for containing a heat pack, and a heat pack within the compartment and in heat transferring relationship with the liner for transferring heat from the heat pack to the liner and any beverage contained within the liner.
The objective is also achieved by providing a method of self-heating a beverage urn with beverage contained within a liner when removed from any source of power by performing the steps of heating a heat pack contained within the urn and in thermal communication with the liner at a first location where hot beverage is added to the liner using an electrical power available for heating the heat pack at the first location, moving the urn to a second location remote from the first location after the hot beverage has been added, and heating the beverage at the remote location solely by the step of conveying heat from the heat pack to the liner and the hot beverage contained within the liner.
Also, obtainment of the objective is achieved by provision of a method of self-heating a beverage urn with beverage contained within a liner when removed from any source of power by performing the steps of heating a heat pack when separated from the urn using electrical power, installing the heat pack into a heat pack compartment within the urn and in thermal communication with the liner after the heat pack has been heated to a preselected temperature, and heating the beverage solely by the step of conveying heat from the heat pack to the liner and the hot beverage contained within the liner.